The present invention relates to a reciprocating drive apparatus designed to reciprocate a traveling member of an automatic molding removing machine.
A typical automatic molding removing machine for automatically removing moldings from a molding machine has a reciprocating drive apparatus for horizontally reciprocating a chuck member that holds moldings. In one type of a generally known reciprocating drive apparatus, a pinion that is provided on the rotary shaft of an electric motor attached to a traveling member is meshed with a rack secured to a machine frame so that the traveling member is reciprocated in response to the drive of the motor.
In another conventional reciprocating drive apparatus, a rod of a cylinder that is attached to the machine frame is secured to a traveling member so that the traveling member is reciprocated in response to the operation of the cylinder.
These prior art apparatuses suffer, however, from the following problems.
In the former prior art apparatus, a high-output and high-torque electric motor is used under the necessity of moving the traveling member at high speed in order to shorten the time required to effect molding removal. In this case, since the overall weight of the traveling member having the motor attached thereto increases and consequently the inertia acting on the traveling member when traveling increases, complicated braking control must be conducted for the motor in order to stop the traveling member within a short time and with a high degree of accuracy and a shock absorber is needed, which results in a rise in the overall cost of the apparatus.
In the latter prior art apparatus, a cylinder having an axial length corresponding to the travel of the traveling member is needed, which results in an increase in the overall size of the molding removing machine. In particular, when the travel of the traveling member is long, a large-sized cylinder is needed, which results in a rise in the overall cost of the apparatus.